Across
- 2. 4.6 ____ years old is the age of Earth
- 4. red eye planet
- 6. sphere containing the earth
- 9. hypothesis that life on Earth maintains itself
- 12. rocky inner planets
- 15. sphere containing all the other spheres
- 17. hit the planet causing the death of the dinosaurs
- 18. early stage of a star
- 19. gas giant planets
- 20. has a coma when close to a star
Down
- 1. rare metal found in rock from 65 mya
- 2. sphere where life exists
- 3. sphere containing the air
- 5. name of our galaxy
- 7. sphere containing water in all its forms
- 8. size of our star
- 10. mismanaged river in the USA that doesn't flow to the Pacific anymore
- 11. theory explaining the origin of the universe
- 13. when a orbit is oval instead of circular
- 14. created one of the hypothesis from this unit
- 16. changes to the earth's axis